This study will examine among former Mexican American gang members the associations between adolescent, early young adulthood and young adult-specific risk factors and the outcomes of infection with HIV, hepatitis B and C, sexually transmitted infections, and related infection risks. This application proposes to follow up a cohort of adolescent Mexican American male gang (n=160) members in San Antonio previously identified in a NIDA funded study (R01 DA08604). This sample will serve as t1 of the proposed longitudinal cohort study. For time two (a retrospective five year measurement point) and time three (current interview), we will re-interview the same respondents and recruit an additional cohort of 150 individuals. We will use specific analytical constructs from the age-graded theory of informal social control and Hispanic culture to explain the health consequences associated with the transition from adolescence to young adulthood that may be critical for HIV intervention efforts. Data collection will consist of the administration of a questionnaire (t2 and t3) that will include standardized assessments, biological assessments and qualitative life history interviews that will be conducted with a subset of the sample. The aims of the study are the following: 1. Determine the prevalence (tested) of HIV, HBV, HCV, and STIs, (chlamydia trachomatis, syphilis and herpes simplex virus-2) infection in young adulthood (n=310). 2. Determine the prevalence of HIV, hepatitis and STI infection risks, including high risk sexual behaviors, injecting drug use, non-injecting heroin and stimulant use and high-risk drug and sexual networks in young adulthood (n=310) 3. Determine, among gang members recruited ten years ago (n=160) whether the young adulthood outcomes of testing positive for HIV, hepatitis and STIs and infection risks are associated with the adolescent risk factors of informal social control processes and risk behaviors (T1). 4. Determine whether the young adulthood outcomes of testing positive for HIV, hepatitis and STIs and infection risks are associated with the early young adulthood factors of informal social control processes and incarceration history (T2) (n=310). 5. Determine whether the young adulthood outcomes of testing positive for HIV, hepatitis and STIs and infection risks are associated with the young adulthood informal social control processes, risk behaviors, and cultural factors (T3) (n=310). 6. Characterize qualitatively the complex processes, culture and context, associated with significant risk factors that are related to HIV, hepatitis, and STI's infection and infection risks during the life course trajectories from adolescence to young adulthood. Our research will significantly contribute to the development of selective HIV intervention preventions and policy discourse that take into consideration the distinct life course trajectories of gang affiliated populations. PUBLIC HEALTH RELEVANCE: The proposed study provides a unique opportunity to seek a comprehensive understanding of the long term health consequences of youth gang membership for infection with HIV, hepatitis B and C and STIs and related infection risks. The study will provide a unique opportunity to investigate the risk of an HIV epidemic within the context of a community with a high HCV and STI prevalence. Findings from this study can be used to develop HIV intervention strategies culturally appropriate for high risk Mexican American young adult populations